1. Field of the Invention
The present invention is related to a semiconductor memory device in which memory cells which can electrically reprogram data are stacked in three dimensions.
2. Description of the Related Art
While the process of miniaturization demanded by the reduction of semiconductor memory device design rules is gradually becoming more and more difficult, a plurality of semiconductor memory devices in which memory elements are arranged in three dimensions have been proposed in order to increase the degree of memory integration. For example, Japan Laid Open Patent 2003-078044, U.S. Pat. No. 5,599,724. U.S. Pat. No. 5,705,885, and Masuoka et al., “Novel Ultrahigh-Density Flash Memory With a Stacked-Surrounding GateTransistor (S-SGT) Structured Cell”, IEEE TRANSACTIONS ON ELECTRON DEVICES, VOL. 50, NO 4, pp 945-951, April 2003